Many telecommunication devices or telephony endpoints operate using the Voice-over IP (VoIP) standard. VoIP telecommunications differs from the legacy circuit-switched telephony systems in many ways. One major difference is the ability for a VoIP telephony endpoint to be nomadic or even mobile whereas a circuit-switched telephony endpoint is in a fixed and known location. Thus, when a circuit-switched telephony endpoint makes an emergency call (e.g., a 911 call), the location of the telephony endpoint (and therefore the caller) is known because that particular telephony endpoint has been assigned a physical address that is stored in a database. The address may be easily included in the call to an emergency dispatcher located in a Public Safety Answering Point (PSAP). The PSAP dispatcher may then send aid directly to the caller.
VoIP telephony endpoints, however, may be moved and operated virtually anywhere an Internet connection is available. As a result, the exact location of the telephony endpoint (caller) cannot be precisely known to the PSAP dispatcher. One administrative solution requires a VoIP telephony service provider to collect a valid registered address for the customer. When a customer makes an emergency call over the VoIP network, the telephone service provider (or their emergency services provider) uses the registered address on file and passes it to the PSAP dispatcher. This works well enough if the customer has not relocated the telephony endpoint since the last registered address update. But, if the customer is accessing his VoIP telephony services from a location that is not the same as the registered address on file, the location data sent to the PSAP will be inaccurate and may lead to significant delays in receiving any needed aid.
What is needed is a technique to better produce an accurate location of a VoIP telephony endpoint to a PSAP dispatcher when the VoIP telephony endpoint makes an emergency call.